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 #    contributors may be used to endorse or promote products derived
 #    from this software without specific prior written permission.
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#pragma once
#include "Core/API/Texture.h"

namespace Falcor
{
    /** This class holds data and texture used to render text.
        It represents a mono-spaced font.
    */
    class Font
    {
    public:
        using UniquePtr = std::unique_ptr<Font>;
        using UniqueConstPtr = std::unique_ptr<const Font>;

        ~Font();

        /** Create a font object.
            \return New object, or throws an exception if creation failed.
        */
        static UniquePtr create();

        /** The structs contains information on the location of the character in the texture
        */
        struct CharTexCrdDesc
        {
            float2 topLeft; ///< Non-normalized origin of the character in the texture
            float2 size;    ///< Size in pixels of the character. This should be used to initialize the texture-coordinate when rendering.
        };

        /** Get the texture containing the characters
        */
        Texture::SharedPtr getTexture() const { return mpTexture; }

        /** Get the character descriptor
        */
        const CharTexCrdDesc& getCharDesc(char c) const
        {
            assert(c >= mFirstChar && c <= mLastChar);
            return mCharDesc[c - mFirstChar];
        }

        /** Get the height in pixels of the font
        */
        float getFontHeight() const { return mFontHeight; }

        /** Get the width in pixels of the tab character
        */
        float getTabWidth() const { return mTabWidth; }

        /** Get the spacing in pixels between 2 characters. This is measured as (start-of-char-2) - (start-of-char-1).
        */
        float getLettersSpacing() const { return mLetterSpacing; }

    private:
        Font();
        Font(const Font&) = delete;
        Font& operator=(const Font&) = delete;

        bool loadFromFile(const std::string& fontName, float size);

        static const char mFirstChar = '!';
        static const char mLastChar = '~';
        static const uint32_t mCharCount = mLastChar - mFirstChar + 1;
        static const uint32_t mTexWidth = 1024;

        Texture::SharedPtr mpTexture;
        CharTexCrdDesc mCharDesc[mCharCount];
        float mFontHeight;
        float mTabWidth;
        float mLetterSpacing;
    };
}
